This paper proposes an electronic image stabilization algorithm based on efficient block matching on the plane. This algorithm uses a hexagonal search algorithm, and uses the bit-planes to estimate and compensate for ...This paper proposes an electronic image stabilization algorithm based on efficient block matching on the plane. This algorithm uses a hexagonal search algorithm, and uses the bit-planes to estimate and compensate for the translational motion between video sequences at the same time;As for the rotary motion vector generated in the video sequences, in order to highlight the intensity change of the image sequence, the algorithm firstly conducts Laplace transform for the reference frame, then select a number of characteristics at the image edge to make block matching with the current frame, calculate and compensate for the rotational movement that may exist finally. Through theoretical analysis and simula-tion, we prove that, as for a mixed translational and rotational motion video sequences, the proposed algorithm can reduce required time for block matching computation ,while improving the accuracy of the electronic image stabilization.展开更多
Recently, an edge adaptive image stegano- graphic method based on least significant bit （LSB） matching revisited （EA-LSBMR） has been proposed, which holds good visual quality and proper security under appropriate ...Recently, an edge adaptive image stegano- graphic method based on least significant bit （LSB） matching revisited （EA-LSBMR） has been proposed, which holds good visual quality and proper security under appropriate embedding rates. However, from the extensive experiments to EA-LSBMR, we find that the discrete Fourier transform （DFT） spectrum of pixelpairs differences histogram still reveals the presence of a secret message even in a low embedding rate. To enhance the security, a modified scheme is proposed in this paper, which can defeat the above-mentioned analysis and keep the visual quality better than EA-LSBMR in higher embedding rates. Experimental results using a latest universal steganalysis method have demonstrated the proposed method＇s good performance.展开更多
球形译码(Sphere Decoding,SD)能够有效地实现极化码最大似然译码的误码性能,文章提出基于比特翻转的多重球形译码树搜索(Multiple Sphere Decoding Tree Searches Based on Bit-Flipping,BF-MSDTS)算法进一步提升短极化码的性能,该算...球形译码(Sphere Decoding,SD)能够有效地实现极化码最大似然译码的误码性能,文章提出基于比特翻转的多重球形译码树搜索(Multiple Sphere Decoding Tree Searches Based on Bit-Flipping,BF-MSDTS)算法进一步提升短极化码的性能,该算法通过扩大半径搜索和翻转不可靠比特提升误码性能,同时利用搜索终止准则和固定可靠比特降低复杂度,有效地解决了多重球形译码树搜索(Multiple Sphere Decoding Tree Searches,MSDTS)算法低信噪比下误码性能不如循环冗余校验(Cyclic Redundancy Check,CRC)辅助的串行消除列表(CRC Aided Successive Cancellation List,CA-SCL)算法的问题.仿真结果表明,在低信噪比时,当误码率为10-4时,与CA-SCL算法比较,提高了0.41dB,与MSDTS算法比较,提高了1.17dB.提出的BF-MSDTS算法的误码性能在较差的信道环境下优于现有的MSDTS算法以及CA-SCL算法.展开更多
A differential modulation scheme using space-time block codes is put forward. Compared with other schemes, our scheme has lower computational complexity and has a simpler decoder. In the case of three or four transmit...A differential modulation scheme using space-time block codes is put forward. Compared with other schemes, our scheme has lower computational complexity and has a simpler decoder. In the case of three or four transmitter antennas, our scheme has a higher rate a higher coding gain and a lower bit error rate for a given rate. Then we made simulations for space-time block codes as well as group codes in the case of two, three, four and five transmit antennas. The simulations prove that using two transmit antennas, one receive antenna and code rate of 4 bits/s/Hz, the differential STBC method outperform the differential group codes method by 4 dB. Useing three, four and five transmit antennas, one receive antenna, and code rate of 3 bits/s/Hz are adopted, the differential STBC method outperform the differential group codes method by 5 dB, 6. 5 dB and 7 dB, respectively. In other words, the differential modulation scheme based on space-time block code is better than the corresponding differential modulation scheme展开更多
文摘This paper proposes an electronic image stabilization algorithm based on efficient block matching on the plane. This algorithm uses a hexagonal search algorithm, and uses the bit-planes to estimate and compensate for the translational motion between video sequences at the same time;As for the rotary motion vector generated in the video sequences, in order to highlight the intensity change of the image sequence, the algorithm firstly conducts Laplace transform for the reference frame, then select a number of characteristics at the image edge to make block matching with the current frame, calculate and compensate for the rotational movement that may exist finally. Through theoretical analysis and simula-tion, we prove that, as for a mixed translational and rotational motion video sequences, the proposed algorithm can reduce required time for block matching computation ,while improving the accuracy of the electronic image stabilization.
基金supported in part by the National Science Foundation of China for Distinguished Young Scholars under Grant No. 61025013Sino-Singapore JRP under Grant No. 2010DFA11010+1 种基金National NSF of China under Grant No. 61073159Fundamental Research Funds for the Central Universities under Grant No. 2009JBZ006
文摘Recently, an edge adaptive image stegano- graphic method based on least significant bit （LSB） matching revisited （EA-LSBMR） has been proposed, which holds good visual quality and proper security under appropriate embedding rates. However, from the extensive experiments to EA-LSBMR, we find that the discrete Fourier transform （DFT） spectrum of pixelpairs differences histogram still reveals the presence of a secret message even in a low embedding rate. To enhance the security, a modified scheme is proposed in this paper, which can defeat the above-mentioned analysis and keep the visual quality better than EA-LSBMR in higher embedding rates. Experimental results using a latest universal steganalysis method have demonstrated the proposed method＇s good performance.
文摘球形译码(Sphere Decoding,SD)能够有效地实现极化码最大似然译码的误码性能,文章提出基于比特翻转的多重球形译码树搜索(Multiple Sphere Decoding Tree Searches Based on Bit-Flipping,BF-MSDTS)算法进一步提升短极化码的性能,该算法通过扩大半径搜索和翻转不可靠比特提升误码性能,同时利用搜索终止准则和固定可靠比特降低复杂度,有效地解决了多重球形译码树搜索(Multiple Sphere Decoding Tree Searches,MSDTS)算法低信噪比下误码性能不如循环冗余校验(Cyclic Redundancy Check,CRC)辅助的串行消除列表(CRC Aided Successive Cancellation List,CA-SCL)算法的问题.仿真结果表明,在低信噪比时,当误码率为10-4时,与CA-SCL算法比较,提高了0.41dB,与MSDTS算法比较,提高了1.17dB.提出的BF-MSDTS算法的误码性能在较差的信道环境下优于现有的MSDTS算法以及CA-SCL算法.
基金This project was supported by the National Natural Science Foundation of China (60172018) .
文摘A differential modulation scheme using space-time block codes is put forward. Compared with other schemes, our scheme has lower computational complexity and has a simpler decoder. In the case of three or four transmitter antennas, our scheme has a higher rate a higher coding gain and a lower bit error rate for a given rate. Then we made simulations for space-time block codes as well as group codes in the case of two, three, four and five transmit antennas. The simulations prove that using two transmit antennas, one receive antenna and code rate of 4 bits/s/Hz, the differential STBC method outperform the differential group codes method by 4 dB. Useing three, four and five transmit antennas, one receive antenna, and code rate of 3 bits/s/Hz are adopted, the differential STBC method outperform the differential group codes method by 5 dB, 6. 5 dB and 7 dB, respectively. In other words, the differential modulation scheme based on space-time block code is better than the corresponding differential modulation scheme
